Brush cutting operations have a variety of purposes. Some major purposes are clearing utility rights-of-way and road sides of obstructing vegetation and thinning trees for land management. In such situations, it is of course desirable to retard the regrowth of cut vegetation and maximize the period of time before the clearing or thinning operation needs to be repeated. One method of retarding regrowth is to spray the cut areas with suitable chemicals. Since cut vegetation, such as tree stumps, tends to heal over most immediately, it is important that any spraying operation be conducted as soon as possible after the cutting. For this reason, it is not unusual for a cutting contractor to be required to spray within ten minutes of cutting.
The need for prompt spraying of cut areas is difficult to meet because of the lack of availability of brush cutting equipment both suitable for clearing rights-of-way and/or tree thinning, and capable of spraying operations. Currently, the most common method of carrying out the spraying is to have a worker on foot with a back-carried chemical tank and a hand-held sprayer following the brush cutting machine. This procedure is very tedious and labor intensive and, therefore, quite costly. In addition, the procedure submits the worker to undesirable working conditions. Since the worker must maintain a safe distance from the brush cutting machine, the procedure also involves an unavoidable delay in the spraying following the cutting of the brush. Moreover, because of the relative remoteness of the cutting operation and the unavoidable covering over of cut areas with cut brush and debris, it is very difficult for the worker to accurately identify the areas that require spraying. Even when the areas are recognized, the nature of hand spraying generally leads to uneven coverage. The result tends to be overspraying and/or uneven spraying with areas of inadequate spraying.
Another problem associated with known brush cutting equipment is that elements mounted on the work head can obstruct cutting operations and are subject to contamination caused by contact with mud and debris and to damage caused by their becoming snagged on vegetation and other objects. This makes it difficult to mount gripping apparatus and actuators therefor on or near the work head without increasing repair and maintenance costs.
Spraying attachments for lawn mowers are disclosed in U.S. Pat. Nos. 2,737,340, granted Mar. 6, 1956, to R. A. Bonini; No. 2,908,444, granted Oct. 13, 1959, to A. R. Mullin; No. 3,017,121, granted Jan. 16, 1962, to V. W. Carlson; No. 3,100,371, granted Aug. 13, 1963, to P. C. Redmon; and No. 3,857,515, granted Dec. 31, 1974, to M. M. Zennie. The Bonini attachment is mounted on a platform of a lawn mower along with a motor, and is operable simultaneously or independently of the cutter and traction mechanisms to spray liquid. The location of the sprayer, which is connected to a platform-mounted compressor by a hose, is unclear. Mullin discloses a spraying attachment for a lawn mower having a rotating cutting bar similar to a fan blade. The spraying attachment is mounted on the drive shaft above the cutting bar. Centrifugal force carries liquid through circumferential slots, and the liquid is deflected downwardly so that it is dispensed only beneath the mower. Carlson and Zennie each disclose an attachment for a power lawn mower that has a perforated manifold mounted in a fixed position laterally offset from the mower. The Carlson attachment is powered by the exhaust of the mower. The Zennie attachment is operated by a blower powered by the mower engine. Redmon discloses an attachment for a lawn mower having a hopper mounted on the mower housing that dispenses liquid onto the blade or in the blade's path only when the mower is moving.
U.S. Pat. Nos. 3,982,697, granted Sep. 28, 1976, to H. E. Maples, discloses a spraying attachment for a type of mower used on golf course greens. The liquid is received from a remote source through an intake mounted above the mower and is dispensed behind the mower. The attachment has valves to control the dispensing of the liquid. U.S. Pat. No. 4,551,968, granted Nov. 12, 1985, to B. A. Samuelsson, discloses a sprayer mounted on a self-propelled harvester. The sprayer includes a tubular liquid applicator with a plurality of nozzles. The applicator is positioned behind a front cutting device. The applicator sprays weed killer following the cutting of a crop but before the crop residue is deposited.
U.S. Pat. No. 2,331,373, granted Oct. 12, 1943, to F. A. Campbell, discloses a liquid discharge appliance for fire fighting, horticulture, or spraying buildings. The appliance resembles a rigid hose and has tubes that are extended telescopically relative to each other by a fluid flowing into the appliance. Mower attachments having a housing with a blade-exposing opening are disclosed in U.S. Pat. Nos. 3,241,302, granted Mar. 22, 1966, to R. O. Barry; No. 4,509,315, granted Apr. 9, 1985, to N. Giguere; and No. 4,802,327, granted Feb. 7, 1989, to C. A. Roberts.
Gripping mechanisms are shown in U.S. Pat. Nos. 4,269,241, granted May 26, 1981, to L. Hickman; No. 4,376,340, granted Mar. 15, 1983, to M. Ramun et al.; No. 4,446,897, granted May 8, 1984, to J. Kurelek; and No. 4,491,163, granted Jan. 1, 1985, to J. Kurelek. The Ramun et al. device is an attachment for a backhoe in which the gripping jaws have inner edges with a scissor-like action. The other three patents disclose tree felling apparatus in which the tree is gripped during the cutting.